The field of positron emission tomography is currently severely limited by the high cost of camera instrumentation imposed by the basic cost of the crystal technology required for efficient detection of the 511 keV radiation. As a result of this high cost, cameras are severely limited in axial field of view to typically 12 - 16 cm and still cost several million dollars. This technology utilizing the radiopharmaceutical 18FDG shows exceptional promise in the detection of small cancerous lesions at the earliest possible point in development with great potential patient benefits. However, the high camera cost together with the extremely limited field of view will likely prevent the practical clinical application of this powerful diagnostic technique. This project will develop a new type of PET detector system based on modem high energy straw detector technology which will lower the base materials cost of PET cameras by an order of magnitude. Pilot studies have demonstrated the clear potential of this relatively simple technology and work in Phase I will define a multi detector design to be constructed in Phase II. If successful this technology could make this powerful diagnostic technology available for practical wide scale clinical use. PROPOSED COMMERCIAL APPLICATIONS: If successful a low cost straw detector based PET camera would have enormous commercial potential as it together with the radiopharmaceutical 18FDG could form one of the primary means of diagnosing small cancerous lesions.